Cross Origin Filter with embedded Jetty

Question

I'm trying to get a CrossOriginFilter working with a couple of embedded Jetty servers, both running on our internal network. Both are running servlets, but I need server A's web page to be able to post to server B's servlets. I think I need to add ACCESS_CONTROL_ALLOW_ORIGIN to a CrossOriginFilter but finding out how to do this with an embedded Jetty instance with no web.xml isn't proving to be easy. I get the following error message in the browser when trying to access server b's serlvets

No 'Access-Control-Allow-Origin' header is present on the requested resource

Im using angularjs to post to the other server's servlets in a controller.

And here is the code for one of the servers (both are pretty much the same)

Server server = new Server(httpPort);

ResourceHandler resource_handler = new ResourceHandler();
resource_handler.setDirectoriesListed(true);
resource_handler.setWelcomeFiles(new String[] { "index.html" });
resource_handler.setResourceBase("./http/");

ServletHandler handler = new ServletHandler();
handler.addServletWithMapping(ServerPageRoot.class, "/servlet/*");

FilterHolder holder = new FilterHolder(CrossOriginFilter.class);
holder.setInitParameter(CrossOriginFilter.ALLOWED_ORIGINS_PARAM, "*");
holder.setInitParameter(CrossOriginFilter.ACCESS_CONTROL_ALLOW_ORIGIN_HEADER, "*");
holder.setInitParameter(CrossOriginFilter.ALLOWED_METHODS_PARAM, "GET,POST,HEAD");
holder.setInitParameter(CrossOriginFilter.ALLOWED_HEADERS_PARAM, "X-Requested-With,Content-Type,Accept,Origin");

handler.addFilter(holder );

HandlerList handlers = new HandlerList();
handlers.setHandlers(new Handler[] { resource_handler, handler,new DefaultHandler() });
server.setHandler(handlers);
server.start();

Answer 1

A few points:

• Don't use ServletHandler naked like that. The ServletHandler is an internal class that ServletContextHandler uses.
• The ServletContextHandler is what provides the needed ServletContext object and state for the various servlets and filters you are using.
• The ServletContextHandler also provides a place for the overall Context Path declaration
• The ServletContextHandler is also the place for Welcome Files declaration.
• Don't use ResourceHandler, when you have DefaultServlet available, its far more capable and feature rich.

Example:

Server server = new Server(httpPort);

// Setup the context for servlets
ServletContextHandler context = new ServletContextHandler();
// Set the context for all filters and servlets
// Required for the internal servlet & filter ServletContext to be sane
context.setContextPath("/");
// The servlet context is what holds the welcome list 
// (not the ResourceHandler or DefaultServlet)
context.setWelcomeFiles(new String[] { "index.html" });

// Add a servlet
context.addServlet(ServerPageRoot.class,"/servlet/*");

// Add the filter, and then use the provided FilterHolder to configure it
FilterHolder cors = context.addFilter(CrossOriginFilter.class,"/*",EnumSet.of(DispatcherType.REQUEST));
cors.setInitParameter(CrossOriginFilter.ALLOWED_ORIGINS_PARAM, "*");
cors.setInitParameter(CrossOriginFilter.ACCESS_CONTROL_ALLOW_ORIGIN_HEADER, "*");
cors.setInitParameter(CrossOriginFilter.ALLOWED_METHODS_PARAM, "GET,POST,HEAD");
cors.setInitParameter(CrossOriginFilter.ALLOWED_HEADERS_PARAM, "X-Requested-With,Content-Type,Accept,Origin");

// Use a DefaultServlet to serve static files.
// Alternate Holder technique, prepare then add.
// DefaultServlet should be named 'default'
ServletHolder def = new ServletHolder("default", DefaultServlet.class);
def.setInitParameter("resourceBase","./http/");
def.setInitParameter("dirAllowed","false");
context.addServlet(def,"/");

// Create the server level handler list.
HandlerList handlers = new HandlerList();
// Make sure DefaultHandler is last (for error handling reasons)
handlers.setHandlers(new Handler[] { context, new DefaultHandler() });

server.setHandler(handlers);
server.start();

Answer 2

managed to get it working by doing

FilterHolder holder = new FilterHolder(CrossOriginFilter.class);
holder.setInitParameter(CrossOriginFilter.ALLOWED_ORIGINS_PARAM, "*");
holder.setInitParameter(CrossOriginFilter.ACCESS_CONTROL_ALLOW_ORIGIN_HEADER, "*");
holder.setInitParameter(CrossOriginFilter.ALLOWED_METHODS_PARAM, "GET,POST,HEAD");
holder.setInitParameter(CrossOriginFilter.ALLOWED_HEADERS_PARAM, "X-Requested-With,Content-Type,Accept,Origin");
holder.setName("cross-origin");
FilterMapping fm = new FilterMapping();
fm.setFilterName("cross-origin");
fm.setPathSpec("*");
handler.addFilter(holder, fm );